Layered double hydroxides (LDHs) exhibit excellent catalytic performance due to their unique two-dimensional (2D) layered structure, adjustable chemical composition, and tunable interlayer ion types and contents. However, when employed as a catalyst, LDH materials still suffer from several drawbacks, such as poor electrical conductivity and a tendency to agglomerate. To further improve their catalytic performance, a variety of effective modification strategies have been adopted, including electronic structure modulation, morphological control, and interface engineering.

Nickel‒iron (NiFe)-LDH demonstrates outstanding catalytic performance for the oxygen evolution reaction (OER) in alkaline media. Layered LDHs are typically grown directly on nickel foam (NF). The layered architecture of LDH, in combination with the three-dimensional (3D) network of NF, facilitates the exposure of abundant active sites and enables efficient bubble release, as well as rapid electron and mass transport. However, the specific surface areas (SSAs) of NF and nickel net (NN), which are commonly employed as catalyst supports, are relatively limited. To achieve higher current densities, a larger amount of the catalyst needs to be loaded onto the current collector to provide more accessible active sites. Nevertheless, simply increasing the thickness of the LDH layer often leads to agglomeration, which masks active sites and inevitably compromises the intrinsic catalytic efficiency, resulting in decreased OER activity. Therefore, this approach is inefficient for further performance enhancement.

Currently, most studies primarily enhance the OER activity of NiFe-LDH catalysts loaded on NF by modifying the skeleton of NF. However, although extensive efforts have been devoted to surface modification of NF, the role of the porous structure itself has not been thoroughly explored.

Making full use of the pore space is an effective strategy to increase the SSA of catalyst supports. Therefore, reconstructing more efficient microstructures to harness the intra-pore space of NF and NN — thereby increasing catalyst loading and the exposed reaction area on electrodes — is crucial for achieving high catalytic activity in NiFe-LDH.

Lei et al. recently proposed a general strategy in Frontiers of Materials Science for fabricating a series of electrodes consisting of NiFe-LDH grown on porous carbon nested in NF or NN. The electrodes exhibit significant OER activity and stability. The porous carbon nested in NF or NN provides a large SSA, enabling substantial loading of NiFe-LDH and thereby increasing the number of active sites, which enhances the overall OER catalytic performance. As a result, the NiFe-LDH/C-NF-M-0.1-1200 electrode only requires overpotentials of ~230 and ~280 mV to drive a current density of 100 and 800 mA·cm⁻² in 1.0 mol·L⁻¹ KOH, respectively. Moreover, it operates stably at 500 mA·cm⁻² for 14 h. This strategy provides a new approach for the rational design of efficient electrocatalysts for electrochemical applications.
DOI: 10.1007/s11706-026-0760-5